Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/02—Printing inks
  • C09D11/03—Printing inks characterised by features other than the chemical nature of the binder
  • C09D11/037—Printing inks characterised by features other than the chemical nature of the binder characterised by the pigment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/02—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the alkali- or alkaline earth metals or beryllium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
  • B01J13/02—Making microcapsules or microballoons
  • B01J13/06—Making microcapsules or microballoons by phase separation
  • B01J13/14—Polymerisation; cross-linking
  • B01J13/18—In situ polymerisation with all reactants being present in the same phase
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/124—Duplicating or marking methods; Sheet materials for use therein using pressure to make a masked colour visible, e.g. to make a coloured support visible, to create an opaque or transparent pattern, or to form colour by uniting colour-forming components
  • B41M5/165—Duplicating or marking methods; Sheet materials for use therein using pressure to make a masked colour visible, e.g. to make a coloured support visible, to create an opaque or transparent pattern, or to form colour by uniting colour-forming components characterised by the use of microcapsules; Special solvents for incorporating the ingredients
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K9/00—Use of pretreated ingredients
  • C08K9/10—Encapsulated ingredients
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/41—Organic pigments; Organic dyes
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
  • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
  • D06P1/0004—General aspects of dyeing
  • D06P1/0016—Dye baths containing a dyeing agent in a special form such as for instance in melted or solid form, as a floating film or gel, spray or aerosol, or atomised dyes
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
  • D06P5/00—Other features in dyeing or printing textiles, or dyeing leather, furs, or solid macromolecular substances in any form
  • D06P5/001—Special chemical aspects of printing textile materials
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/093—Encapsulated toner particles

Definitions

• the invention also relates to a process for the production of these microcapsules and their use for the production of printing and painting inks and lacquers, for the production of toners for electrophotography, for the coloring of plastics and synthetic fibers and for the production of heat-sensitive recording materials.
• Microencapsulated solids are known per se. These are in particular metals, metal oxides, pigments, color formers and other inorganic or organic particles which tend to agglomerate or whose surface properties are to be standardized for the respective intended use. They are used in many areas of technology, for example in the manufacture of printing inks and varnishes, heat-sensitive recording materials and toners for electrophotography.
• DE-A-40 15 753 discloses a process for the production of microcapsules which contain color formers dissolved in core oils.
• the polymerization is carried out using oil-soluble radical initiators in an oil-in-water emulsion.
• the vinyl monomers used dissolve in the hydrophobic core solvent, while the resulting polymer is insoluble and forms the stable capsule wall around the liquid core after phase separation.
• the invention was based on the object of providing microencapsulated solid particles which are notable for good performance properties and do not have the disadvantages mentioned above during their production.
• microcapsules with solid core defined at the outset were found.
• microcapsules encasing solid particles according to the invention are produced from 30 to 100% by weight, preferably 40 to 100% by weight, of one or more vinyl monomers (monomers I).
• microcapsules according to the invention can contain up to 70% by weight, preferably up to 40% by weight, of one or more bi- or polyfunctional monomers (monomers II) and up to 40% by weight, preferably up to 30% by weight. % of other monomers (monomers III) have also been built up.
• Monomers I and II are hydrophobic unsaturated compounds which can be used individually or in the form of mixtures.
• Preferred monomers I are styrene, methyl, ethyl, n-propyl, n-butyl and 2-ethylhexyl acrylate and / or methacrylate.
• Suitable monomers II are bifunctional and polyfunctional monomers, primarily divinyl and polyvinyl monomers, which bring about a crosslinking of the capsule wall during the polymerization.
• the crosslinking makes the polymer shell of the solids difficult to melt and thus receives a much better temperature stability. At the same time, it is also stable against attack by solvents that would dissolve the uncrosslinked polymers.
• Preferred divinyl monomers are ethanediol diacrylate and dimethacrylate, 1,3-butanediol dimethacrylate, methallyl methacrylamide and allyl methacrylate. 1,3- and 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol diacrylate and dimethacrylate and divinylbenzene are particularly preferred.
• Preferred polyvinyl monomers are trimethylolpropane triacrylate and trimethacrylate, pentaerythritol triallyl ether and triacrylate, and pentaerythritol tetraacrylate and tetramethacrylate.
• microcapsules enveloping solid particles according to the invention are produced by suspension polymerization of the monomers I and, if desired, the monomers II and / or III in an aqueous medium in which the monomers are dispersed.
• the radical initiators used here are oil-soluble and start and control the polymerization in a known manner through their thermal decomposition.
• oil-soluble peroxo and azo compounds can be used as radical initiators, advantageously in amounts of 0.1 to 5% by weight, based on the weight of the monomers, which can be used individually or as mixtures.
• Preferred radical initiators are tert-pentyl peroxypivalate, dilauroyl peroxide, tert-pentyl-2-ethylhexanoate, dibenzoyl peroxide, tert-butyl peroxy-2-ethyl hexanoate, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (tert .-butylperoxy) hexane, cumene hydroperoxide, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile); 2,2'-azobis (2,4-dimethylvaleronitrile) and 2,2'-azobis (2-methylbutyronitrile).
• Tert-butyl peroxyneodecanoate di (3,5,5-trimethylhexanoyl) peroxide, tert-butyl peroxypivalate, 4,4'-azobisisobutyronitrile and dimethyl-2,2'-azobisisobutyrate are particularly preferred. These have a half-life of 10 hours in a temperature range from 30 to 100 ° C.
• the polymerization according to the invention it can be advantageous to regulate the molecular weight of the resulting polymers.
• This can be done in a known manner by adding chain-transferring reagents during the polymerization.
• Suitable substances for this are, for example, aliphatic alcohols such as methanol, isopropanol and 1-buten-2-ol, carbon tetrachloride and mercaptans such as tert-dodecyl mercaptan and thioglycolic acid esters such as ethyl and 2-ethylhexylthioglycolate.
• the size of the solid particles should be in a range customary for microcapsules, i.e. approximately at 10 nm to 100 ⁇ m.
• the preferred particle sizes depend on the particular application. In general, however, larger particles can also be encapsulated by the process according to the invention.
• Suitable inorganic solids are, for example, metals, such as aluminum, lead, iron, cobalt, nickel, chromium, copper, silver, gold, palladium, platinum, rhodium and zinc, and their alloys, and preferably metal oxides, such as, in addition to silicon dioxide and magnesium oxide, especially magnetic oxides (for example magnetite, nickel and cobalt oxide) and oxides acting as pigments.
• metals such as aluminum, lead, iron, cobalt, nickel, chromium, copper, silver, gold, palladium, platinum, rhodium and zinc
• metal oxides such as, in addition to silicon dioxide and magnesium oxide, especially magnetic oxides (for example magnetite, nickel and cobalt oxide) and oxides acting as pigments.
• Colorants are particularly preferred for the microencapsulation according to the invention, i.e. inorganic and organic pigments, dyes that are only soluble in water to a certain percentage (up to 10% by weight), as well as color formers (compounds that are themselves colorless or barely colored and their color in contact with an electron acceptor by donating an electron or picking up a proton).
• the pigments used for the production of printing inks and lacquers, for electrophotography, for textile dyeing and textile printing and the color formers used in heat and pressure-sensitive recording materials are suitable, for example.
• the weight ratio of solid to the sum of monomers I, II and III is generally between about 10: 1 and 1:10.
• the amount of monomer required in an individual case depends on the desired application and, of course, particularly on the size of the solid particles. At least the amount of monomer required to monomolecularly cover the entire surface of the finely divided solid must be used which can be calculated using known formulas.
• the polymer shells have thicknesses of up to approximately 10 ⁇ m.
• the solid must be finely dispersed in water.
• the dispersion can be carried out in a manner which is customary, for example, for pigments.
• the pigment is expediently predispersed in a dissolver in the presence of water and one or more dispersants. Since the average diameter of the pigment particles should be less than 1 ⁇ m in the case of coloring pigments in order to achieve high color strengths, a customary further dispersion is usually connected, for example in a stirred ball mill or a bead mill. In some cases predispersion can also be dispensed with.
• Suitable dispersing agents are the water-soluble nonionic and ionic polymers commonly used (both of which are also referred to as protective colloids) and nonionic, cationic and anionic surfactants.
• suitable dispersing agents is to be made in individual cases and is determined by the solid to be encapsulated. Decision criteria are e.g. easy dispersibility of the solid in water to the desired particle size, high solids content of the dispersion with low viscosity before and after microencapsulation and good storage stability of the dispersions after microencapsulation.
• Preferred water-soluble nonionic dispersing agents are, for example, polyvinyl alcohol, partially hydrolyzed polyvinyl acetates, polyvinyl pyrrolidone and its copolymers such as vinyl pyrrolidone / vinyl acetate copolymers, polyacrylic and methacrylamide and copolymers which contain the respective monomers, cellulose derivatives such as hydroxyethyl and methyl cellulose, rubber cellulose arabic and their mixtures.
• the nonionic polymers are generally used in amounts of 0.1 to 2000% by weight, preferably 0.5 to 1000% by weight, based on the solid to be encapsulated.
• water-soluble ionic dispersing aids are polyacrylic acid and methacrylic acid and copolymers containing the respective monomers, copolymers based on maleic acid and its anhydride, e.g. with methyl vinyl ether, diisobutene and styrene, polymers of sulfoethyl and sulfopropyl acrylate and methacrylate, N-sulfoethyl-maleimide, 2-acrylamido-2-alkyl sulfonic acids, styrene and vinyl sulfonic acid and copolymers of these monomers.
• Naphthalenesulfonic acid / formaldehyde condensates, phenolsulfonic acid / formaldehyde condensates and polyacrylic and polymethacrylic acid are particularly preferred.
• the amount of ionic polymers used is generally 0.1 to 1000% by weight, preferably 0.5 to 500% by weight, based on the solid to be encapsulated.
• surfactants can also be added as additional dispersing agents.
• Suitable nonionic surfactants are, for example, sorbitan esters such as sorbitan laurate, alkyl or aryl polyglycol ethers such as dodecyl polyglycol ether (with 18 ethylene oxide units).
• Examples of cationic surfactants which may be mentioned include alkylammonium and alkylpyridinium salts such as cetyltrimethylammonium bromide and laurylpyridinium chloride.
• Suitable anionic surfactants are, for example, alkyl and alkylarylsulfates and sulfonates such as sodium lauryl sulfate and nonylphenylsulfonate, alkyl polyglycol ethers and alkylphenol polyglycol ether sulfates and sulfonates such as sodium lauryl polyglycol ether sulfate and nonylylphenol polyglycol ether 50
• the surfactants are generally added in amounts of 0.1 to 100% by weight, preferably 0.5 to 50% by weight, based on the solid to be encapsulated.
• the size distribution of the solid particles can be matched to the respective intended use.
• the particles have sizes of approximately 10 nm to 100 ⁇ m.
• the microencapsulation process according to the invention can be carried out as usual: the solid is initially charged with the dispersing aids, dispersed in water.
• the subsequent addition of monomers can be carried out in one step, but the monomers can also be metered in gradually during the polymerization, which is particularly advantageous if one wishes to achieve a layered structure of the polymer shell.
• the radical initiator or the radical initiator mixture and, if desired, the regulator can also be added directly with the monomers or gradually. It is also possible to continue the dispersion after the addition of monomers and starters.
• the dispersion is then heated with intensive stirring to the temperature at which the radical initiator disintegrates in sufficient quantities.
• the polymerization is then carried out at this temperature. It may also be favorable to then slightly increase the temperature of the mixture for a few hours, also with stirring.
• the polymerization is carried out at 20 to 100 ° C., preferably at 40 to 80 ° C.
• the polymerization is expediently carried out at normal pressure, but it is also possible to work under reduced or slightly increased pressure, that is to say in the range from 0.5 to 5 bar.
• the reaction times are usually 1 to 10, usually 2 to 7 hours.
• the rate of polymerization can be determined by the choice of temperature and the amount Radical starters and controllers can be controlled in a manner known per se.
• the microencapsulated solids produced according to the invention can be used in the form of the aqueous dispersions obtained, or they can be dried, for example, by spray or freeze drying and used as a powder, or redispersed in water before they are used.
• microencapsulated solids according to the invention can be used advantageously for many purposes. This applies in particular to the encapsulated colorant particles.
• Microencapsulated pigments according to the invention are outstandingly suitable for producing printing inks (for both paper and textile printing), paints and varnishes. Their use is particularly favorable for water-dilutable systems, since the aqueous dispersions of these pigments are very stable and therefore storable and can be diluted with water without any problems.
• the paints and varnishes to be obtained have high color strength and at the same time excellent hiding power and are characterized by the particular economy of their application.
• encapsulated pigments according to the invention can advantageously be used for the production of toners for electrophotography.
• the different electrical chargeability of the different toner pigments has a particularly disadvantageous effect when producing color copies.
• These encapsulations can be significantly reduced by microencapsulation, since the surface properties and thus also the chargeability of the pigment particles are standardized. Since the pigments usually have to be incorporated into the so-called toner resins at high temperatures (about 100 to 200 ° C.), microencapsulation with polymers which are difficult to melt is recommended, ie the monomers I are preferably polymerized together with the crosslinking monomers II .
• Microencapsulated pigments can also be used effectively in the dyeing of plastics and synthetic fibers, in particular polyamide fibers.
• the dyeing is carried out by incorporating the pigments directly into the respective polymer melts at high temperatures up to over 300 ° C, often using extruders.
• non-encapsulated pigments can partially dissolve or react with the polymer melt, which leads to a loss of color strength.
• Temperature-stable microencapsulation means that pigments that are not stable can be effectively protected even under these conditions.
• the monomers I are preferably polymerized together with the crosslinking monomers II.
• microencapsulated color formers are in the production of heat-sensitive recording materials. These are generally paper or plastic films which have been coated by spreading the aqueous dispersion of color former and color developer (electron acceptors such as, above all, phenol derivatives and organic acids and their salts).
• color former and color developer (electron acceptors such as, above all, phenol derivatives and organic acids and their salts).
• the coloring reaction between the two components is triggered by selective heat exposure with a thermal printer.
• An undesired advance development, i.e. A quality-reducing background staining already during the production of the thermal paper can be prevented by microencapsulation of the color former.
• the capsule walls must be easily meltable, i.e. they preferably consist of polymers of the monomers I.
• the K values listed in the following examples for the water-soluble polymers were in each case according to H. Fikentscher, Cellulosechemie, Volume 13, pp. 48-64 and 71-74 (1932) in 1% strength by weight aqueous solution (or at K values less than 30 in 5% strength by weight aqueous solution) at 25 ° C.
• the dispersion was then heated to 60 ° C. in a glass flask with a propeller stirrer (400 rpm) and held at this temperature for 2 hours.
• the mixture was then polymerized at 65 ° C for 4 h.
• Microencapsulated pigment with a particle size of ⁇ 1 to about 100 ⁇ m was obtained.
• Microencapsulated pigment with a particle size of ⁇ 1 to about 3 ⁇ m was obtained.
• CI Pigment Red 81: 1 (as in Example 2) and 64 g of a non-neutralized polyacrylic acid (K value 20) were dissolved in 240 g of water in a Dispermat (Teflon disc 9 cm in diameter, 300 g of glass balls 3 mm in diameter, 3500 rpm) dispersed for 3 hours.
• K value 20 a non-neutralized polyacrylic acid
• Microencapsulated pigment with a particle size of ⁇ 1 to about 5 ⁇ m was obtained.
• Example 7 In Examples 7 to 12 listed in Table 2, 27.5 g of C.I. Pigment Yellow 185 (as in Example 1) as in Example 2.
• microencapsulation was carried out analogously to Example 3.
• the polymerization was carried out analogously to Example 3.
• Microencapsulated pigment with a particle size of ⁇ 2 to about 6 ⁇ m was obtained.
• the polymerization was carried out analogously to Example 3.
• Microencapsulated pigment with a particle size of ⁇ 1 to about 25 ⁇ m was obtained.
• Example 15 to 17 listed in Table 3 55 g of the pigment indicated in each case in the amount of water likewise specified was dispersed analogously to Example 14 using 66 g of vinyl pyrrolidone / vinyl acetate 1.5: 1 copolymer (K value 25). The further treatment was also carried out analogously to Example 14 with the monomer / starter mixture specified there.
• Example 3 55 g of the diaminofluorane Pergascript® Black I-R (Ciba-Geigy) and 66 g of polyvinylpyrrolidone (K value 30) were dispersed in 154 g of water as in Example 3. The further treatment was carried out analogously to Example 13.
• Microencapsulated color formers were obtained with a particle size of ⁇ 1 to about 25 microns.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Dispersion Chemistry (AREA)
• Wood Science & Technology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Textile Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Manufacturing Of Micro-Capsules (AREA)
• Developing Agents For Electrophotography (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)

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Citations (6)

• 1991
  • 1991-11-15 DE DE4137619A patent/DE4137619A1/de not_active Withdrawn
• 1992
  • 1992-11-05 EP EP92118950A patent/EP0542133A1/fr not_active Withdrawn
  • 1992-11-13 KR KR1019920021342A patent/KR930009648A/ko not_active Application Discontinuation
  • 1992-11-13 JP JP4303458A patent/JPH05212271A/ja not_active Withdrawn
  • 1992-11-13 CA CA002082892A patent/CA2082892A1/fr not_active Abandoned

Patent Citations (6)

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